/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.common.networking;


/**
 * Class for storing a network response.  If the response has not been
 * set when {@link #getResponse} has been called, this method will
 * block until {@link #setResponse} is called.
 */
public class NetworkReplyObject
{

    private Object response = null;
    private boolean responseGiven = false;
    private final int networkReplyId;


    /**
     * The constructor.
     *
     * @param networkReplyId The unique identifier for the network message
     *                       this object will store.
     */
    public NetworkReplyObject( int networkReplyId )
    {
        this.networkReplyId = networkReplyId;
    }

    /**
     * Sets the response and continues <code>getResponse()</code>.
     *
     * @param response The response.
     * @see #getResponse
     */
    public synchronized void setResponse( Object response )
    {
        if ( response == null )
        {
            throw new NullPointerException( );
        }
        this.response = response;
        this.responseGiven = true;
        notify( );
    }

    /**
     * Gets the response. If the response has not been set, this method
     * will block until {@link #setResponse} has been called.
     *
     * @return the response.
     */
    public synchronized Object getResponse( )
    {
        if ( response == null )
        {
            try
            {
                while ( ! responseGiven )
                {
                    wait( );
                }
            }
            catch ( InterruptedException ie ) {}
        }

        return response;
    }

    /**
     * Gets the unique identifier for the network message this
     * object will store.
     *
     * @return the unique identifier.
     */
    public int getNetworkReplyId( )
    {
        return networkReplyId;
    }

    /**
     * Interrupts any thread waiting for a response.
     */
    public synchronized void interrupt( )
    {
        responseGiven = true;
        notify( );
    }
}
